Wheel brake



Oct 259 R. H. ROSENBERG WHEEL BRAKE Filed Jan. 27, 1925 Patented Oct.25, 1927.

"UNITED'ISTATES 1,646,932 PATENT OFFICE RALPH H. ROSENBERG, OF SYRACUSE,NEW YORK, ASSIGNOR TO.AMERICA .1\T CAIBJEIE GOMPAN Y, INC.

WHEEL BRAKE.

,App'lication filed January This invention is 'an improvement in brakesfor wheels or other rotary members and is of that type in which thereare a pair of brake shoes which ,may be operated to grip an annular partof tween.

As one important feature the brake shoes are so mounted that when ineither braking or released position they may float in a direction at anangle to the rotor surface, and thereby permit uniform braking actionand prevent binding in caseythe rotor surface departs from true circularform due to lack of truing operation during manufacture or assembly, or.due to expansion or contraction on changes in temperature.

As a further feature the brake shoes are so designed that when engagedthey leave the major portion of the brake rotor surface exposed for heatradiation so that the liability of overheating or burning the brakelinings during long continued application of the brakes is reduced to aminimum. The ends of the brake shoes also act as scrapers to remove anymud or other foreign matter that may splash or drip on the exposed rotorsurface. This arrangement also permits two independently operable pairsof brakes to be mounted for engagement with a single rotor.

As another important feature the operating mechanism is directlyconnected to one only of the pair of shoes, the support for the twoshoes being so designed and mounted that the two shoes are applied orreleased sin'iultaneously. i

As a further feature the parts are so mounted .that in case of wear ofthe brake shoe linings one only of the brake shoes need be readjusted tocompensate for change in the thickness of the linings of both shoes.

As a further feature-the parts are so designed that changes in thelength or position of the operating rod or other mechanism connectedtoone brake shoe may be compensated for by merely adjusting the positionof the other shoe.

One important object of my invention is to provide a constructionwhereby I can secure the foregoing advantages by the use" of the minimumnumber of parts, simple in design, inexpensive to manufacture andassemble, certain and positive in operation, easy to adjust, and easyand inexpensive to reline or repair. v

the rotor therebe- 27, 1925. Serial 170.},988.

My improved construction may be employed for controlling rotors invarious types of apparatus, and operates equally efficiently both as tobraking and release, irrespective of the direction of rotation of therotor. -The rotor may have its brake surface in a radial plane with thebrake shoes axially movable upon opposite sides thereof, or it may be inthe form of the more usual cylindrical drum with one shoe at the outersurface and the other at the inner surface, and both movable in adirection having a radial component.

The two shoes are preferably pivotally mounted upon pins journaled in apivoted arm and upon opposite sides of the rotor other, whereby upon therotation of either pin the shoes are given a. relative movement towardor away from each other,

Preferably one pin is rotatable to secure the desired normal spacing andis normally locked against rotation, while the other is rotated by theoperating mechanism to apply orrelease the brake.

In the accompanying drawing I have shown one embodiment of my invention,but of course it will be obvious that many changes may be made in thedetails of construction within the spirit of my invention withoutdeparting from the scope, as defined in the appended claims. Thedrawings are to be considered in an illustrative rat-her than in alimiting sense.

In these drawings:

Fig. 1 is an end elevation showing the rotor in dot and dash lines.

Fig. 2 is a face elevation, and

Fig. 3 is a transverse section on the line 33 of Fig. 1.

' I have illustrated my invention in a form adapted for use in:connection with a rotor in the form of a brake drum with a substantiallycylindrical peripheral wall 10 presenting opposed inner and outersurfaces their surfaces substantially parallel and of approximately thesame curvature as that of the wall 10. The shoes may be made fromcastings, stampings or in any other suitable manner, and are; providedwith linings 13 which may be held in place in any suitable manner andmay be of the same general type as is commonly employed for thispurpose. The two shoes are pivotally mounted upon a pair-of pins whichare disposed upon opposite sides of the rotor wall 10, and substantiallyparallel to' the latter. The connection between'each pin and the brakeshoe may be of any suitable character, but preterably permits a slightrocking of the shoe so that uniform engagement of the entire length ofthe shoe with the brake drum may be secured Merely as an example of sucha connection each pin may have a collar 16 for engagement with the sideof the shoe, and against one side wall of the shoe. This collar may beformed integral with the pin. Between the side walls of the shoe the pinmay have a second collar 17 held against longitudinal movement in onedirection bya cotter pin 18. This collar is held against the cotter pinby a spring 19 which serves not only to hold the brake shoe against thecollar 16, but prevents rattling due to lost motion endwise of the pinor about the pin as a center.

The two pins 14 and 15 are mounted in a member which has certain freedomof move ment in a direction at an angle to the wall applying the brake.

10 of the rotor. As shown, this member is in the form of an arm 20pivoted on a pin 21 which may be carried by any suitable form ofsupport, as for instance a bracket 22 clamped to some nonerotary partcoaxial with the rotor. The pin 21 is preferably disposed adjacent tothe periphery of the brake drum and the arm extends in a directionapproximately tangential to the drum so that the swinging of the armmoves the pins 14 and 15 toward and from the wall 10 and approximatelyradially of the rotor.

As the arm 20 is free to swing to bring either shoe into engagement withthe brake drum, it will be apparent that upon moving either shoe towardthe other the spacing between the shoes will be reduced and the brakedrum may be gripped by the simultaneous and equal action of the twoshoes.

-For the same reason the normal spacing between the shoes may be variedby the movement of either shoe toward the other. This permits adjustmentto take care of wearand resulting variation in the thickness of thebrake shoe linings. In practice I provide means for moving one shoe tosecure normal spacing for released position, and provide means formoving the other shoe in The movement of the shoes is preferablyaccomplished by providing the pins 14 and 15 with eccentric porneee eeations and means for rotating them. As shown, each pin has the shoesupporting end eccentric in respect to the end journaled .in the arm 20.Thus by rotating either pin the shoe carried thereby is moved toward orfrom the brake drum. The pin for the outer shoe 11 is normally rigidlyclamped against rotation in the arm 20, but can be rotated to adjust thenormal spacing between the shoes. As shown the arm has a split bearingfor the pin 14 and a pair of clamping bolts 23 which may be tightened tolock the -pin against rotation. The outer end 24 of the pin may beprovided with flattened faces whereby it may be readily engaged by awrench to turn the pin when the bolts 23 are loosened.

The other pin 15 has a similar shoe bearing portion eccentric in respectto the portion journaled in the arm 20. The outer end 25 of this pin maybe provided with a lever 26 or other means for rotating the pin to applythe brakes.

Due tothe fact that the lever arm 26 is very long compared to theeccentricity of the shoe bearing portion of the pin 15, it

will be apparent that a comparatively light pull on the lever arm willexert great pressure on the brake shoe to grip the brake band and resistor prevent rotation of the latter.

As the brake linings wear to lesser thickness the lever arm 26 must bemoved to a greater distance to apply the brake, but this can be readilycompensated for by adjustment of the brake shoe 11 toward the brake shoe12 to restore the normal or original spacing of the brake shoes.

If the parts be ositioned as shown in Fig, l, the inner s 0e 12 will beentirely free from the brake drum when the brake is released, and theouter brake shoe 11 will ride very lightly on the brake drum. Frictionalresistance offered by this riding of the shoe' is practically nil, dueto the fact that the direction of movement of the shoe toward the drumhas a very decided horizontal component. By adjusting the bracket 22 sothat the centers of the shoes come at a lower point than is shown inFig. 1. the brake drum may be entirely relieved of any weight of theshoes 'When the brake is released. As the shoes extend along less thanone-half the circumference of the drum. it will be apparent that asecond pair of shoes may be mounted diametrically opposite to the pairshown and operated entirely independently thereof, or in conjunctiontherewith. If the brake is used on a vehicle, one pair of brake shoesmay serve for the foot brake and' the other for an emergency brake.

As one important advantage of my construction the pivotal mounting ofthe brake shoecarrying arm 20 permits the latter to swing duringrotation of the brake drum and accommodate itself to any non-cylinas thetwo shoes merely ride along the drum and move in and out with variationsin the contour of the latter. By avoiding the necessity of accuratelyturning and accurately mounting the brake drum, I secure a very decidedreduction in the costof manufacture and installation of the apparatus.

Furthermore there is no binding or failure of proper operation, shouldthe brake drum expand upon; undue heating, or in case of contractionfrom severe co1d.

There are practically no parts in the entire device which require anymachining operations except the pins 14,15 and 21, and the journals forthe latter.

By theterm brake shoes as used in the foregoing specification and in theclaims, I do not wish to imply thatthe invention is limited in its usesolely to resisting or preventing the rotation of a rotor. shoes areclamping members, and when engaged with the drum resist or preventrelative rotation of the drum and the part carrying the shoes. Manyfeatures of my improved construction are equally applicable for use in aclutch for connecting one rotatable member to a drum forming the otherrotatable member. a.

Having thus described my invention, what .1 claim as new I V and desireto secure by Letters Patent is:

1. The combination with a rotor of a member having a portion freelymovable in a direction at an angle to the surface of the rotor, a pairof brake shoes carried by said member upon opposite sides of the rotor,

and means for moving one only of the shoes with respect to the membertoward the other and means for moving one only of the shoes toward theother to adjust the normal spacing of the shoes.

3. The' combination with a rotor of a member having a portion freelymovable in a direction at an angle to the surface of the till rotor, apair of brake shoes carried by said member u'pon opposite sides of therotor, and a pin rotatably mountedin sald member and having an eccentricportion for moving one of said shoes toward the other.

4. The combination with a rotor 'of a member having a portion freelymovable in a direction at an angle to the surface of the rotor, a pairof brake shoes carried by said The brake member upon opposite sides ofthe rotor, a pin rotatably mounted in said member and having aneccentricportion for moving one of said shoes toward the other, andanoperating lever for rotating said pin to apply both brake shoes to therotor.

5. The combination with a rotor of a member having a portion freelymovable in a direction at an angle to the surface of the rotor, a pairof brake shoes carried by said member upon opposite sides of the rotor,a

pin rotatably mounted in said member and having an eccentric poigtionfor moving one of said shoes toward the other, and means for normallylocking said pin against rotation.

6. The combination with a rotor of v a member having a portion freelymovable in a direction at an angle to the surface of the rotor, a pairof brake shoes carried by said member upon opposite sides of the rotor,means for moving one of said shoes toward and from the other to vary thenormal spacing, and means for moving the other .shoe toward and from thefirst mentioned one to grip the rotor between said shoes.

v 7. The combination with v a rotor of a member having a portion freelymovable in a direction .at an angle to the surface of the rotor, a pairof brake shoes carried by said member upon opposite sides of the rotor,and a pair of pins journaled in said member and having eccentricportions serving as supports for said shoes, and operating meansconnected to one only of said ins for rotating the latter to apply bothrake shoes to the rotor. v 9. The combination with a rotor of a memberhaving a portion freely movable in adirection at an angle to the surfaceof the rotor, a pair of brake shoes carried by said member upon oppositesides of the rotor,

an eccentric normally locked against rotation, but rotatable to adjustthe position of one shoe, and an eccentric for moving the other shoe togrip the rotor between the shoes.

i 10. The combination with a rotor of a pair of brake shoes having theirsurfaces disposed" substantiallyparallel to the surface of the rotor,and upon opposite sides thereof, a pair of eccentric. pins forsupporting the brake shoes, and means for rotating one of said pins toeffect relative movement of the brake shoes toward or from each other.

11. The combination with a rotor of a pair of brake shoes having theirsurfaces ported surfaces, one'inside of and thefother outside of thedrum, means for pivotally connecting one shoe to said arm With anormally fixed pivotal center, means for pivotally connecting the othershoe to said arm, and means for moving the pivotal center of the secondmentioned shoe to bind the drum between the shoes. g Y

13. The combination with a cylindrical brake drum of an arm pivotallymounted adjacent'to the periphery and extending in a general tangentialdirection, a pair of shoes having spaced approximately parallelsurfaces, one inside of and the other outside of the drum, an eccentricfor adjusting one of said shoes radially of the drum and in respect tosaid arm, and an operating lever supby said 'arm and connected to theother of said shoes for moving it substantially radially to grip thebrake drum between the shoes. 1

. 14. The combination with a cylindrical and having eccentric portionsfor supporting said shoes. and means for rotating one of said pins togrip the brake drumbetween the two shoes. x

15'. The combination with a rotor of a member having .a portion'freely-movable in a direction at an angle to the surface of the rotor, apairof brake shoes carried by said member upon opposite sides of therotor, and means for effecting a relative movement "theirotor, saidmember. permitting limited jfloatingimove ment of the two brake shoes topermiti'equal gripping action against op- T'posite sides-inf said rotor.

16. The combination with a rotorof a member having a portion-"freelymovable in I a direction at'an angle to the surface of the rotor, apairoff-brake shoes upon opposite sides. of the'rotor, a pair of pivotpins car- ..:-ried by said member and supporting said brake shoes anddisposed substantially .par-

maaeaa allel to each other. and to the surface of the rotor, and meansfor moving said pivot pins to engage said brake shoes with said rotor,

said member .permitting limited radial floating m'ovementof the brakeshoes to insure equal gripping action of the latter on said rotor.

17. The combination with a cylindrical brake drum of an armpivotallymounted adjacent to the periphery. andexte'nding in a generaltangential directionila pair of.

brake shoes having approximately parallel surfaces, one on the insideand the other on the outside of the drum, and an operatingleveiifpivotally connected to said arm adjacent. to the outer end of thelatter for effecting movement of said brake shoes in pins permittinglimited floating movement of said shoes to insure equal gripping actionof the-latter on said section.

19. The combination with a rotor of a member having a portion freelymovable in a direction at an angleto the surface of the rotor, 21. pairof brake shoes mounted for oscillation on said member and positionedwith respect to the rotor, the free'end of said member being adapted toswing at an angle to the surface of the rotor, a pair of bralie shoescarried by said member at its free end and upon opposite sides of therotor, and means for moving the shoes toward. each other toiapply'themto the rotor. :21. The combination with a rotor of a support mounted toswing freely in a di-, rection at an angle to the surface of the rotor,a pair of brake shoes carried by the said support at its free end andupon opposite sides of 'the rotor, and means for moving one only of theshoes toward the other to apply them to the rotor.

Signed at New York, in the county of New York and State of New York,this 2tth day of January, A. D. 1925.

' RALPH H. ROSENBERG.

a rotor of a 7

